The present invention relates generally to an improved touch sensor for detecting the presence of an object and measuring the relative position of the objects, adapted to be attached to a spindle of machine tools such as general-purpose milling machines, machining centers and numerical control lathers, and more particularly to a device for supporting a stylus in a touch sensor.
Such a touch sensor is designed to electrically sense the workpiece of an object by the contact of the stylus therewith, and furthermore, inside a casing of the touch sensor, the stylus is supported at the axial center position by a spring so as to be allowed to move relative to the casing when the stylus comes into contact with the workpiece; consequently never receiving an excessive pressure.
For example, the Japanese Patent Publication (examined) No. 58-17402 open to the public on Apr. 7, 1983 discloses a touch sensor, wherein the base part of the stylus is provided with three bars projecting radially therefrom, of which the end parts are supported by three respective pairs of balls placed in the casing. However, such structure as employed in the prior art requires the increased number of constituent members, i.e. three bars and three pairs of balls (six balls), and further requires the precise processing of the corresponding parts of the stylus and casing where the bars and the balls are mounted, thereby resulting in an increased cost of production.